ALKYNE

CHAPTER 7 — ALKYNES ALKYNES

MULTIPLE CHOICE

1. Approximately Approximatel y how long is a carbon-carbon carbon-carb on triple bond of an alkyne? a. 110 pm b. 121 pm c. 135 pm d. 156 pm ANS: B 2. What is the approximate C CC bond angle in propyne? a. 90 b. 109 c. 120 d. 180 ANS: D 3. How many many alkynes are there with the molecular formula C 6H10? a. 4 b. 5 c. 6 d. 7 ANS: D 4. How many many terminal alkynes alkynes are there with the molecular molecular formula C 7H12? a. 5 b. 7 c. 8 d. 9 ANS: C 5. Which atomic orbitals overlap to form the carbon-carbon carbon-carbo n triple bond of an alkyne? a. 2 s + s + 2 s; s; sp + sp + sp sp;; 2 p + p + 2 p b. sp + sp + sp sp;; sp + sp + sp sp;; 2 p + p + 2 p c. sp + sp + sp sp;; 2 p + p + 2 p; p; 2 p + p + 2 p 2 2 d. sp + sp + sp ; sp + sp + sp sp;; 2 p + 2p ANS: C 6. Which atomic orbitals overlap to form the carbon-carbon carbon-carbo n single bond of 1-propyne? a. 2 s + s + sp sp 2 b. sp + sp + sp sp 3 c. sp + sp + sp sp d. sp2 + sp + sp3 ANS: C

Brown Organic Chemistry 6e

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7. What is the smallest cycloalkyne that is stable at room temperature? a. cyclohexyne b. cyclononyne c. cyclododecyne d. cycloeicosyne ANS: B 8. What is the IUPAC IUPAC name of the following compound? CH3CH2CH2CCCH(CH3)2 a. 1-isopropyl-1-pentyne b. 2-methyl-3-heptyne 2-methyl-3-heptyne c. 6-methyl-4-heptyne d. isopropyl propyl ethyne ANS: B 9. What is the IUPAC IUPAC name of the following compound? (CH3)2CHCH2CCCH(CH3)2 a. 2,6-dimethyl-3-heptyne b. 2,6-dimethyl-4-heptyne 2,6-dimethyl-4-heptyne c. 1,1,5,5-tetramethyl-2-pentyne d. 4-nonyne ANS: A 10. What is the IUPAC IUPAC name of the following compound?

a. b. c. d.

3,4-dimethyl-1-hexen-5-yne 4-ethynyl-2-vinylbutane 4-ethynyl-2-vinylbutane 3-methyl-4-vinyl-1-pentyne 4-ethynyl-3-methyl-1-pentyne

ANS: A 11. What is the IUPAC IUPAC name of the following compound

a. vinylcyclohexane b. allylcyclohexane allylcyclohexane c. ethynylcyclohexane d. acetylcyclohexane


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ANS: C 12. What is the IUPAC name of the following compound?

a. b. c. d.

( R)-4-methyl-2-hexyne (S )-4-methyl-2-hexyne ( R)-3-methyl-4-hexyne (S )-3-methyl-4-hexyne

ANS: B 13. What is the IUPAC name for the following compound?

a. b. c. d.

( R)-3-methyl-1-penten-4-yne (S )-3-methyl-1-penten-4-yne ( R)-4-methyl-4-penten-1-yne (S )-4-methyl-4-penten-1-yne

ANS: A 14. Which of the following is the strongest acid? a. propane b. cyclopropane c. propene d. propyne ANS: D 15. Which of the following has the lowest p K a? a. butane b. 1-butene c. 1-butyne d. 2-butyne ANS: C


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16. What is the correct assignment of the acid, base, conjugate acid and conjugate base in the following equilibrium?

a. b. c. d.

1 =

acid; 2 = base; 1 = acid; 2 = base; 1 = base; 2 = acid; 1 = base; 2 = acid;

3 =

conjugate acid; 4 = conjugate base 3 = conjugate base; 4 = conjugate acid 3 = conjugate acid; 4 = conjugate base 3 = conjugate base; 4 = conjugate acid

ANS: B 17. What is the major organic product obtained from the following reaction?

a. cyclohexyne b. 1,3-cyclohexadiene c. cyclohexene d. 1,2-diaminocyclohexane ANS: B 18. What is the major organic product obtained from the following reaction?

a. b. c. d.

( E ) 2-butene ( Z ) 2-butene 2-butyne 1-butyne

ANS: C 19. Which sequence of reactions can be used to convert 1-pentene to 1-pentyne a. Treatment with HBr; followed by treatment with NaOH b. Treatment with Br 2; followed by treatment with NaNH 2 c. Treatment with Br 2; followed by treatment with H 2SO4 d. Treatment with Br 2, H2O; followed by treatment with NaOH ANS: B 20. Which sequence of reactions can be used to convert ( Z ) 2-pentene to 2-pentyne a. Treatment with Br 2; followed by treatment with NaNH 2 b. Treatment with Br 2, H2O; followed by treatment with NaOH c. Treatment with Br 2; followed by treatment with H 2SO4 d. Treatment with HBr; followed by treatment with NaOH


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ANS: A 21. What is the major organic product obtained from the following reaction?

a. 2-methyl-3-hexene b. 2-methyl-3-heptyne c. 2-bromo-3-methylbutane d. 2-methyl-2-butene ANS: B 22. What is the major organic product obtained from the following reaction?

a. b. c. d.

1-methyl-4-nonyne 2-methyl-4-nonyne 2-methyl-3-nonyne 3-methyl-4-nonyne

ANS: D 23. What is the major organic product obtained from the following reaction?

a. b. c. d.

( E ) 1,2-dibromobutene ( Z ) 1,2-dibromobutene ( E ) 2,3-dibromobutene ( Z ) 2,3-dibromobutene

ANS: C 24. What is the major organic product obtained from the following reaction?

a. b. c. d.

( E ) 3,4-dibromohexene ( Z ) 3,4-dibromohexene ( E ) 2,3-dibromohexene ( Z ) 2,3-dibromobutene

ANS: A


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25. What is the major organic product obtained from the following reaction?

a. 2,3-dibromobutane b. 2,2,3,3-tetrabromobutane c. 2,3-dibromobutene d. 2,2-dibromobutane ANS: B 26. What is the major organic product obtained from the following reaction?

a. 3,4-dibromohexane b. 3,3-dibromohexane c. ( Z ) 3,4-dibromohexene d. 3,3,4,4-tetrabromohexane ANS: D 27. What is the major organic product obtained from the following reaction?

a. 2,3-dibromobutane b. 2,2,3,3-tetrabromobutane c. 2,3-dibromobutene d. 2,2-dibromobutane ANS: D 28. What is the major organic product obtained from the following reaction?

a. 3,4-dibromohexane b. 3,3-dibromohexane c. ( E ) 3,4-dibromohexene d. 3,3,4,4-tetrabromohexane ANS: B


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a. b. c. d.

butanal cis-2-butene 2-butanol butanone


a. b. c. d.

2-hexanone hexanal 2-hexanol cis-2-hexene

ANS: B 31. What is the major organic product obtained from the following reaction?

a. b. c. d.

butanal cis-2-butene 2-butanol butanone


a. b. c. d.

2-hexanone hexanal 2-hexanol cis-2-hexene

ANS: B


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a. b. c. d.

1 2 3 4


a. b. c. d.

1 2 3 4

ANS: D


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a. b. c. d.

1 2 3 4

ANS: D


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37.

a. b. c. d.

What is the major organic product obtained from the following reaction?

1 2 3 4

ANS: B 38. What type of intermediate s formed in the Hg2 catalyzed hydration of an alkyne?? a. an alcohol b. an enol c. a 1,2-diene d. an epoxide ANS: B 39. What is the major organic product obtained from the following reaction?

a. b. c. d.

1 2 3 4

ANS: C


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a. b. c. d.

1 2 3 4


a. b. c. d.

butane 1-butene cis-2-butene trans-2-butene


a. b. c. d.

1 2 3 4

ANS: B


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a. b. c. d.


ANS: C 44. What is the major organic product obtained from the following reaction?

a. b. c. d.

1 2 3 4


a. b. c. d.


ANS: C


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a. b. c. d.

1 2 3 4

ANS: A 47. What is the best choice of reagent(s) to perform the following transformation?

a. b. c. d.

1 mole of Br 2 2 moles of Br 2 1 mole of HBr 2 moles of HBr

ANS: D 48. What is the best choice of reagent(s) to perform the following transformation?

a. b. c. d.

1 mole of Br 2 2 moles of Br 2 1 mole of HBr 2 moles of HBr

ANS: A


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49. What is the best choice of reagent(s) to perform the following transformation?

a. b. c. d.

H2O; H2SO4 1. 3 moles of NaNH2; 2. H3O+ KMnO4, NaOH, H2O Zn

ANS: B 50. What is the best choice of reagent(s) to perform the following transformation?

a. b. c. d.

H2/Pt H2/Lindlar catalyst Na/NH3 BH3; followed by H2O2, NaOH

ANS: C 51. What is the best choice of reagent(s) to perform the following transformation?

a. b. c. d.

H2/Pt H2/Lindlar catalyst Na/NH3 BH3; followed by H2O2, NaOH

ANS: B 52. What is the best choice of reagent(s) to perform the following transformation?

a. b. c. d.

H2/Lindlar catalyst Na/NH3 (sia)2BH; followed by H 2O2, NaOH BH3; followed by H2O2, NaOH


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ANS: C 53. What is the best choice of reagent(s) to perform the following transformation?

a. b. c. d.

H2/Lindlar catalyst Na/NH3 (sia)2BH; followed by H 2O2, NaOH BH3; followed by H2O2, NaOH

ANS: D 54. What is the major organic product obtained from the following series of reactions?

a. b. c. d.

1 2 3 4

ANS: A 55. What is the major organic product obtained from the following series of reactions?

a. b. c. d.

propanal, CH3CH2CHO 1-propanol, CH3CH2CH2OH butanal, CH3CH2CH2CHO butanone, CH3COCH2CH3


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a. b. c. d.

( E )-5-phenyl-2-pentene 6-phenyl-1-hexene ( Z )-6-phenyl-2-hexene ( E )-6-methyl-3-heptene

ANS: C 57. What is the major organic product obtained from the following series of reactions?

a. b. c. d.

( Z )-2-heptene ( Z )-1,5-heptene 1-heptene heptane


a. b. c. d.

( Z )-2-heptene ( E )-2-heptene 1-heptene heptane

ANS: B 59. Which of the following reagents react with 2-butyne to form ( Z )-2-butene 1. 2. 3.

a. b. c. d.

H2/Lindlar catalyst (sia)2BH followed by CH3COOH Na/NH3 only 1 only 2 only 3 only 1 and 2

ANS: D


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60. Which of the following reagents react with 2-butyne to form butane a. H2/Lindlar catalyst b. H2/Pd c. (sia)2BH followed by CH3COOH d. Na/NH3 ANS: B PROBLEM

1. What is IUPAC name of the following compound?

ANS: ( R)-4-chloro-2-pentyne 2. What is IUPAC name of the following compound?

ANS: (S )-2-chloro-3-hexyne

3. What is IUPAC name of the following compound?

ANS: 1,5-heptadiyne 4. What is IUPAC name of the following compound?

ANS: 2,5-octadiyne


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ANS:

16. Outline how one might achieve the following transformation, showing reagents and the isolated intermediates in the synthesitc scheme.

ANS:



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ANS:

18. Outline how one might achieve the following transformation, showing reagents and the isolated intermediates in the synthetic scheme.

ANS:



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ANS:

20. Outline how one might achieve the following transformation, showing reagents and the isolated intermediates in the synthetic scheme.

ANS:


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ALKYNE

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